A vehicle belonging to Shi’ite militia fighters pulls the body of an Islamic State fighter, who was killed during clashes with Iraqi forces, in Tikrit April 1, 2015. Reuters/Stringer

(Reuters) - The Baghdad bureau chief for Reuters has left Iraq after he was threatened on Facebook and denounced by a Shi'ite paramilitary group's satellite news channel in reaction to a Reuters report last week that detailed lynching and looting in the city of Tikrit.

The threats against journalist Ned Parker began on an Iraqi Facebook page run by a group that calls itself "the Hammer" and is believed by an Iraqi security source to be linked to armed Shi'ite groups. The April 5 post and subsequent comments demanded he be expelled from Iraq. One commenter said that killing Parker was "the best way to silence him, not kick him out."

Three days later, a news show on Al-Ahd, a television station owned by Iranian-backed armed group Asaib Ahl al-Haq, broadcast a segment on Parker that included a photo of him. The segment accused the reporter and Reuters of denigrating Iraq and its government-backed forces, and called on viewers to demand Parker be expelled.

The pressure followed an April 3 report by Parker and two colleagues detailing human rights abuses in Tikrit after government forces and Iranian-backed militias liberated the city from the Islamic State extremist group. Two Reuters journalists in the city witnessed the lynching of an Islamic State fighter by Iraqi federal police. The report also described widespread incidents of looting and arson in the city, which local politicians blamed on Iranian-backed militias.

A Reuters spokeswoman said the agency stood by the accuracy and fairness of its report. Facebook, acting on a request from Reuters, removed a series of threatening posts this week.

The threats appear to be part of a broader power struggle in Iraq. The country is divided between its Shi'ite Muslim majority, which now dominates the government, and its Sunni Muslim minority, which held sway under the late dictator Saddam Hussein. Prime Minister Haidar al-Abadi, a moderate Shi'ite, is attempting to defeat Islamic State – a radical Sunni offshoot of Al Qaeda that has seized huge portions of Iraqi territory – while at the same time trying to mend fences with the broader Sunni community.

The Iraqi military is rebuilding following its collapse last June. That has forced Abadi's government to rely on a constellation of Shi'ite paramilitary forces backed by Iran. The paramilitary forces, which include Asaib Ahl al-Haq, routinely denounce Western media coverage of Iraq's internal conflict.

Abadi is scheduled to meet U.S. President Barack Obama in Washington on April 14 to discuss the campaign against Islamic State.

Rafid Jaboori, a spokesman for Abadi, said the government was "definitely against any message that encourages hatred or intimidation, whether it comes from a local or international network." At the same time, the al-Ahd segment "was primarily a criticism of the government, something that we have to live with" he said.

Jaboori said the environment for media "has improved significantly since this prime minister took over." He advised any foreign journalists who feel threatened to call the Iraqi police for help. Many Iraqis – both Sunni and Shi'ites – do not trust the police, some of whom are believed to have links with the Shi'ite paramilitaries.

Michael Lavallee, a U.S. State Department spokesperson, said: "We condemn all forms of intimidation and violence toward the media as the protection of journalistic freedoms is an essential aspect of all democratic societies."

He said the State Department had spoken with Abadi's office "to raise our concerns about the potentially dangerous atmosphere created by an editorial broadcast on a private Iraqi television network about the Reuters bureau chief and the Reuters staff in Iraq." The State Department "will continue to closely monitor the treatment of international media in Iraq and raise objection to any form of intimidation that may inhibit the ability of the media to perform their work."

The Committee to Protect Journalists, a media advocacy group, says that at least 15 journalists have been killed in Iraq since the beginning of 2013.